Pneumoperitoneum will be established via a blunt entry umbilical port. Two 5mm ports will be placed in the suprapubic and right lower quadrants to facilitate triangulation of instruments during manipulation and lavage. The peritoneal cavity will be thoroughly examined and stage classified according to Hinchey. All patients with faeculant peritonitis will undergo Hartmann's procedure or primary resection and anastomosis according to local preference and excluded from the study on that basis. In the absence of faeculant peritonitis, patients will be randomised to undergo Hartmann's procedure or primary resection and anastomosis (depending on standard practice in the individual unit) or laparoscopic lavage alone. Peritoneal lavage will be performed in all four quadrants using at least 4 litres of warmed saline until the drainage is clear. Intravenous antibiotics will be continued for a minimum of 72hours and oral antibiotics will be continued for one week. Oral fluids will be commenced on the first postoperative day and diet will be introduced subsequently, depending on clinical status. Early mobilisation will be encouraged.